I'll go for somewhat obscure...
Timemaster from Pacesetter Games. I'm a sucker for Time-Bending-Warping-Traveling RPGs. Unfortunately, nobody I played with was and this box has sat on my shelf for many a year, unplayed but not unloved. I tossed around the idea of trying to obtain the license to do a d20 version of Simon Hawke's TimeWars series of books, but I'm afraid I'm the only one who would be interested in playing it... Oh well.